This invention relates the use of a rapamycin in the treatment and inhibition of cardiovascular disease, cerebral vascular disease, and peripheral vascular disease.
Coronary artery disease, the primary form of cardiovascular disease (CVD), is the major cause of death in the United States today, responsible for over 550,000 deaths per year. Cerebrovascular disease is the third leading cause of death in the United States. The etiology of both coronary artery and cerebrovascular diseases is attributed to atherosclerosis. Through its clinical manifestations, atherosclerosis is the major cause of the more than one million heart attacks and approximately 400,000 strokes that occur each year. In addition to the high morbidity and mortality associated with atherosclerosis, it has been estimated that atherosclerosis has cost the United States"" economy over $80 billion each year in lost wages, lost productivity, and medical care costs [Levy, R., Am. Heart J. 110: 1116 (1985)]. A substantial body of evidence has established a relationship between hypercholesterolemia and premature atherosclerosis; the higher the levels of plasma cholesterol, the greater the risk of subsequent heart attack. [Steinberg, D., JAMA 264: 3047 (1991); Lipid Research Clinics Program, JAMA 251: 351 (1984); Rifkind, B., Am. J. Cardiol. 54: 30C (1984)]. However, recent information demonstrates that the atherosclerotic process is far more complicated than a simple correlation with plasma lipid levels, and that there are both systemic and local factors within the vascular wall that play a major role in the progression of this disease [Sulistiyani, Adelman, S. J., Chandrasekaran, A., Jayo, J. and St. Clair, R. W. Arteriosclerosis and Thrombosis 15: 837, (1995)].
Atherosclerosis is a complex disease that is associated with a variety of etiologic factors. Studies have shown that, of the major factors involved, diet-induced hyperlipidemia and genetic defects or abnormalities in lipoprotein metabolism have received the most attention. The local disease process of atherosclerosis is characterized by the accumulation of lipids in the walls of blood vessels. Concomitant with lipid accumulation, there is vascular cell damage resulting in dysfunction of the endothelium, smooth muscle proliferation, and matrix deposition. These changes ultimately result in the formation of what is termed xe2x80x9cplaquexe2x80x9d. As these plaques expand and mature, ruptures in their surface can occur, leading to major thrombotic events. This process, which can occur in essentially all of the blood vessels of the body, results in many of the major disease categories of our time, including coronary artery disease, peripheral vascular disease, myocardial infarction and stroke.
The lipid component of atherosclerotic plaque is of major significance to a variety of vascular diseases. As the plaque develops, there are regions that are rich in cellular material and matrix, underlying a metabolically stable condition. On the luminal surface (contacting the flowing blood) of the plaque, there is a region that further stabilizes the plaque, referred to as the xe2x80x9ccapxe2x80x9d. In these stable regions of the plaque, the cap is relatively thick, and maintains the vessel in a non-threatening elastic state. In contrast to these stable regions, and of up-most importance, there exist other regions of the lesion that are highly enriched in lipid. These regions are the least cellular, with the least amount of connective material for strength and protection from breakage. Cardiac events are often associated with a breakage or rupture of this cap, exposing the flowing blood to the underlying, highly pro-thrombotic material within the plaque, resulting in blockage. Recent studies have found that regions of the plaque most likely to rupture are those with the greatest lipid content. It is typically these lipid rich, soft, pliable regions of the atherosclerotic plaque that give way and rupture (Falk and Fuster et. al), inducing the subsequent thrombotic events that ultimately result in vessel blockage and major vascular events. Therefore, it the lipid-rich regions of the plaque are prominent as contributors to major cardiovascular events such as myocardial infarction and stroke.
In addition to the lipid component, it has recently, been discovered that cells of the immune system also play a major role in all of the processes of atherosclerosis, and thus the process has been described as a chronic inflammatory-fibroproliferative disease of the vascular wall. This is in addition to the lipid deposition typically recognized as atherosclerosis. The attachment of monocytes and T-lymphocytes to the injured endothelium followed by their migration into the intima is one of the first and most crucial steps in lesion development. The co-localization of CD4+ T-cells and macrophages in the lesion, the abundant expression of HLA Class II molecules and the co-stimulatory molecule CD40 and its ligand (CD40L) indicate a contribution of cell-mediated immunity to atherogenesis. A wide variety of studies in animal models suggest that T- and B-cells, and monocytes and macrophages promote lesion progression, and in fact, are in essential for the development of atherosclerotic lesions. Importantly, the local vascular wall immune contribution continues throughout, participating in both plaque expansion as well as rupture. In addition to the local process in the vessel wall, systemic signs of an inflammatory reaction are also associated with lesion development. Thus plasma levels of C-reactive protein and fibrinogen and the white blood cell count are positively correlated to the risk of cardiovascular disease.
Rapamycin is a macrocyclic triene antibiotic produced by Streptomyces hygroscopicus, which was found to have antifungal activity, particularly against Candida albicans, both in vitro and in vivo [C. Vezina et al., J. Antibiot. 28, 721 (1975); S. N. Sehgal et al., J. Antibiot. 28, 727 (1975); H. A. Baker et al., J. Antibiot. 31, 539 (1978); U.S. Pat. No. 3,929,992; and U.S. Pat. No. 3,993,749]. Additionally, rapamycin alone (U.S. Pat. No. 4,885,171) or in combination with picibanil (U.S. Pat. No. 4,401,653) has been shown to have antitumor activity.
The immunosuppressive effects of rapamycin have been disclosed in FASEB 3, 3411 (1989). Cyclosporin A and FK-506, other macrocyclic molecules, also have been shown to be effective as immunosuppressive agents, therefore useful in preventing transplant rejection [FASEB 3, 3411 (1989); FASEB 3, 5256 (1989); R. Y. Calne et al., Lancet 1183 (1978); and U.S. Pat. No. 5,100,899]. R. Martel et al. [Can. J. Physiol. Pharmacol. 55, 48 (1977)] disclosed that rapamycin is effective in the experimental allergic encephalomyelitis model, a model for multiple sclerosis; in the adjuvant arthritis model, a model for rheumatoid arthritis; and effectively inhibited the formation of IgE-like antibodies.
Rapamycin is also useful in preventing or treating systemic lupus erythematosus [U.S. Pat. No. 5,078,999], pulmonary inflammation [U.S. Pat. No. 5,080,899], insulin dependent diabetes mellitus [U.S. Pat. No. 5,321,009], skin disorders, such as psoriasis [U.S. Pat. No. 5,286,730], bowel disorders [U.S. Pat. No. 5,286,731], smooth muscle cell proliferation and intimal thickening following vascular injury [U.S. Pat. Nos. 5,288,711 and 5,516,781], adult T-cell leukemia/lymphoma [European Patent Application 525,960 A1], ocular inflammation [U.S. Pat. No. 5,387,589], malignant carcinomas [U.S. Pat. No. 5,206,018], cardiac inflammatory disease [U.S. Pat. No. 5,496,832], and anemia [U.S. Pat. No. 5,561,138].